Not Applicable
Not Applicable
1. Field of the Invention
This invention relates to an apparatus and method for removing, debriding and/or resecting tissue fragments from a body cavity. In particular, the present invention is directed for use in medical procedures where it may be necessary to remove tissue from a body region. The apparatus and method of the present invention may be especially useful in medical procedures such as orthopedic surgery.
2. Description of the Related Art
Medical procedures involving the removal of tissue from a bone or other region of a body are well known in the art. Of particular interest to the present invention are procedures relating to removal of diseased or damaged tissue of a spinal disk, such as a discectomy.
The spinal disc consists of two types of tissues: the nucleus, and the annulus. The annulus is further divided into the inner and outer annulus. Disc hernias usually consist of a bulge of the nucleus and inner annulus through a rent in a small area of the outer annulus. Partial discectomies are frequently performed when a disc herniation causes pressure on a spinal nerve. The operation consists of removal of the herniated nucleus and portions of the inner annulus. In the past surgeons have used a variety of tools to remove spinal disc tissue during a discectomy.
The simplest tools for disc removal are the scalpel and tweezer-type xe2x80x9cpick-ups,xe2x80x9d which are well known in the art. These tools are very inefficient, as the stringy annular tissues tend to simply move aside and remain attached when these tools are used. Scalpels and pick-ups tend to leave behind fragments of tissue. These fragments can lead to re-herniationxe2x80x94a painful condition that might require a second or even a third operation.
So-called xe2x80x9cpituitary rongeursxe2x80x9d and xe2x80x9ccurettesxe2x80x9d are the most frequently utilized instruments. Some examples of these instruments may be seen in the following U.S. Patent references:
Tools, such as those described in the above cited references, while useful, were not specifically designed to remove disc tissue, and tend to require multiple passes to completely clean out the inner annulus tissue. The use of rongeurs and curettes also tends to leave behind fragments of tissue that may also lead to re-herniation. Furthermore, because these rongeurs and curettes require multiple passes, the operation may be prolonged, possibly leading to increased bleeding and higher infection rates.
Many pituitary rongeurs utilize a single cutting blade at the end of a single, unopposed beam. Actuation of the beam, by means of a drive rod, tends to force the distal shaft to move away from the tissue being cut. An open section in the middle of the beam helps reduce this movement, but does not effectively eliminate the unwanted movement.
Other methods and devices which have been developed in order to improve the effectiveness of a disc removal operation include electrical and laser based cautery. While electrical cautery does effectively destroy disc tissue, it produces heat and smoke in the process. Heat can injure surrounding tissue, including delicate spinal nerves, potentially causing further harm to the patient. In addition, the production of smoke may obscure vision and interfere with the surgeons ability to properly perform the operation. Laser cautery like electrical cautery methods also produce heat and smoke. Low energy lasers tend to be less effective and therefore the disc removal procedure can be prolonged and less than complete. Higher energy lasers produce more heat and smoke and therefore can lead to tissue damage beyond the area of intended removal.
Other devices such as low and high-speed pneumatic or electrical powered rotary burrs are also used. But while they are very useful for removing hard tissues, such as bone, they do not efficiently and effectively remove soft tissues, such as disc material. An example of such a rotary burr is shown in U.S. Pat. No. 5,490,860 to Middle et al., the entire contents of which being incorporated herein by reference. Another type of rotary burr is commercially available and is sold under the name Disc Whisk(trademark) available from Surgical Dynamics Inc. of Norwalk, Conn. Rotary burrs attempt to automate and improve the efficiency of disc removal, but these motorized devices are potentially dangerous when used around the spinal cord and spinal nerves as they develop heat, may grab soft tissue and may penetrate too far.
In light of the above it is clear that there remains a need for an improved, hand-powered tool specifically designed for the removal of diseased soft tissue, such as disc tissue. The current invention improves on the current state of the art by providing a apparatus and method which may be used to efficiently, effectively and safely remove soft tissue from a spinal member such as a disk.
The present invention is directed to a unique reamer tool that may be used to circumferentially resect tissue from a diseased area of a body. The reamer tool of the present invention consists of a sturdy, yet small diameter, hand powered, multi-bladed cutting tool and its method of use.
In at least one embodiment of the invention the reamer tool has a cutting beam which is pivotally engaged to the tool assembly, a push rod and handle in a rack and pinion relationship to allow the cutter beam to be pivoted relative to the distal end of the tool assembly. The cutter beam may have a plurality of cutting blades or surfaces. As the cutter beam is pivoted as a result of compression of the handle, the cutting blades cut into and resect the surrounding tissue.
In at least one embodiment of the invention the reamer tool may be equipped with a variety of devices designed to make the surgical procedure more efficient. For example the reamer tool may have an attached or integrated suction tube which may be used to remove the tissue which has been resected by the cutting action of the cutter beam. Other devices may also be employed.